Interleukin-6-174 Promoter Polymorphism and Susceptibility to Hepatitis B Virus Infection as a Risk Factor for Hepatocellular Carcinoma in Iran

Background: Hepatitis B virus (HBV) is a major risk factor for hepatocellular carcinoma (HCC). Cytokines play an important role in the regulation of immune responses and defense against viral infections. Human interleukin 6 (IL6) is a multifunctional cytokine that participates in these processes. Objective: The aim of this study was to assess the IL6-174 gene polymorphism in patients with chronic hepatitis B virus (HBV) infection as compared with healthy controls in an Iranian population. Materials and Methods: Totals of 297 HBV patients and 368 control individuals were evaluated. Genomic DNA was extracted from peripheral blood and the SSP-PCR (sequence specific primer-polymerase chain reaction) method was applied for genotyping. Results: The frequencies of genotypes C/C, G/G and C/G in HBV cases were 4.7%, 34.3%, 60.9% and in controls were 12.8%, 39.7% and 47.6%, respectively. The frequencies of G and C allele in patients and controls were 78.1%, 21.9% and 67.4%, 32.6 % respectively. There was a significant difference in the frequencies of G/G genotype (CI=1.8-7.1, OR=3.47, P=0.00001) and G allele (CI=1.34-2.23, OR=1.72, P=0.0001) between HBV patients and the control group. Conclusions: These findings suggest that the IL6-174 C/G genotype and the G allele are strongly associated with susceptibility to HBV infection. Demographic information showed that most of the subjects were male (74.4%). According to high frequency of G/G genotype in male participants (63.1%) men probably are more susceptible to hepatitis than women.